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Data Services Products:
EMC-LLNL-G3Dv3
Earth model LLNL-G3Dv3

Summary

Simmons, Myers, Johannesson & Matzel (2012) , is a global-scale model of the crust and mantle P-wave velocity with regional-scale details. The model is parameterized using a spherical tessellation with node spacing of ~1 degree in the upper mantle and ~2 degrees in the lower mantle.

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Description

Name

LLNL-G3Dv3

Title

A global P wave tomography model based on regional and teleseismic travel times

Type

3-D Tomography Earth Model

Sub Type

P velocity

Year

2012

Short Description

LLNL-G3Dv3 is a global-scale model of the crust and mantle P-wave velocity with regional-scale details. The model is parameterized using a spherical tessellation with node spacing of ~1 degree in the upper mantle and ~2 degrees in the lower mantle. Although a spherical tessellation was used to define the lateral positioning of nodes, the model itself is aspherical with Earth’s ellipticity, mantle stretching and undulating discontinuities in the crust and upper mantle built-in. In total, the model consists of 57 layers from the surface to the core and ~1.6 million nodes. 3-D ray tracing and a multi-scale imaging technique (PMTI, Simmons et al., 2011 ) were employed to create the image.

Velocity values are expressed as absolute velocity and percentage variations relative to the layer average.

Model Homepage

Depth Coverage

Surface to core-mantle boundary (CMB)

Areal Coverage

Global (-90°/90°, -180°/180°)

Data Set Description

The model was developed using over 2.8 million groomed and reprocessed P and Pn travel times with events located with the Bayesloc global multiple event location technique (Myers et al. 2007, 2009, 2011 ). Original data sources include the EHB bulletin (Engdahl et al., 1998 ) provided by the International Seismological Centre (ISC), the National Earthquake Information Center (NEIC) bulletin, and a variety of regional bulletins. Additional data are derived from seismic deployments for Peaceful Nuclear Explosions (PNE’ss), large refraction surveys, the USARRAY Transportable Array (TA) and temporary PASSCAL deployments around the world (IRIS ).